MS290 TO 390 CONVERSION OR STICK WITH OEM

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stihlfan7

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I'm looking for some opinions here. I recently got a free Stihl MS290 that has a little scoring on the piston as viewed through the exhaust port. I haven't torn it down yet to examine the cylinder wall to see the extent of the damage. My question is this, if the cylinder is repairable, would y'all go back with a quality aftermarket piston and rings and save the OEM Stihl cylinder or convert to an aftermarket P&C to make it an MS390? This is not going to be a work saw by any means. Just something to have fun with learn about wrenching on saws.
 
The first problem is finding out why it scored in the first place. Then it would just depend on how much you want to spend on it. If the cylinder is good then you would only have to spend 30-40 dollars on a meteor piston. If you wanted to spend 130 on the kit already mentioned, that would be a really nice upgrade. Some of the cheap Chinese kits are pretty good, some are not. I got a farmertec kit for a Husqvarna 50 for $14 delivered. It looked really good and it runs great. I was sceptical about buying it but I knew I could return it if needed.
 
Keep it a 290. But, open exhaust holes up. Carb is large enough to handle it.
A much maligned saw by experts and wannabes, but you’ll be surprised.

Stihl saws and part prices have jumped to outrageous levels.
I’d go aftermarket. Which one……
 
Thanks guys. Knew saw to me but I would guess cracked fuel line/impulse hose. Possibly straight gassed. I know nothing about previous owner or how the saw was used. It is certainly not pristine by any means. I'm gonna go with the big bore kit. No replacement for displacement. Thanks again.
You are on the right track; go big. You may never run that 390 like its design offered, but nobdy is going to our cut you at the woodpile........18" set-up with 3/8" ripping chain.

Makes nice shavings for chipmunk beds; they grab 'em up at night and drag them into the woodpile. Good Luck!
 
a. palmer jr, that's what I was thinking but wondered if it was better to save the OEM cylinder and use an aftermarket piston or gain the CC's. Seems better to gain the CC's. Just have to find a quality P&C kit while keeping the cost down.
 
Did a burned up 310 with a 390 kit. Not the hardest saw to work on but they have their little annoying moments, like installation of the antivibe grommets. Performance is all right with the big bore, but still not in the same league as a pro saw of similar displacement. One point you'll have to address is the restrictive muffler if you want to get max power out of it. Will pull a 20 inch full chisel chain in hardwood with no problem, and will make a decent medium size firewood saw.
 
What do u mean by carb work? I have a 390 and would interested to know
I have changed the carb over to the 044-046 carb. A tad bigger than stock I was told. You generally have to richen the carb up a bit when modding the muffler anyway. Some people have said they move the timing up a degree or two but I'm reluctant to go that route..
 
a. palmer jr, that's what I was thinking but wondered if it was better to save the OEM cylinder and use an aftermarket piston or gain the CC's. Seems better to gain the CC's. Just have to find a quality P&C kit while keeping the costs down.

a. palmer jr, that's what I was thinking but wondered if it was better to save the OEM cylinder and use an aftermarket piston or gain the CC's. Seems better to gain the CC's. Just have to find a quality P&C kit while keeping the cost down.
Most of the kits on ebay aren't very expensive at all. You can check the vendor's feedback to see if any problems arose when buying the kits. Ebay usually makes it good if you get a kit that's sub par..
 
Did 2 rebuilds with Hyway 390 cylinder kits (first one I swapped to Meteor piston) and so far so good. OEM cylinder is open port design. Hyway and Meteor cylinders have more of a closed port influence in their design. There are pop-up pistons available if you are looking for extra compression.
 
I turned a 290 into a 390 last year, took it as far as I could go for extra power. hyway cylinder, widened both ports on it and stuffed a cross pop up with stihl rings into it after opening its windows a hair, ms460 carb, opened the muffler tho I think it still needs further opening and a mesh air filter.
100% a totally different saw, 2x the torque or more than the 290 setup. I run a 20" .325 setup on it and I have no doubt it would pull a similar 3/8 setup without issue.
 
I turned a 290 into a 390 last year, took it as far as I could go for extra power. hyway cylinder, widened both ports on it and stuffed a cross pop up with stihl rings into it after opening its windows a hair, ms460 carb, opened the muffler tho I think it still needs further opening and a mesh air filter.
100% a totally different saw, 2x the torque or more than the 290 setup. I run a 20" .325 setup on it and I have no doubt it would pull a similar 3/8 setup without issue.

I didnt know u could swap the carbs like that
! Does the bigger carb make a difference?

I have a 660 but I want to see how far this 039 will go power wise haha
 

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